In Situ Coupling of Strung Co4N and Intertwined N–C Fibers toward Free-Standing Bifunctional Cathode for Robust, Efficient, and Flexible Zn–Air Batteries
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- 作者：Fanlu Meng ; Haixia Zhong ; Di Bao ; Junmin Yan ; Xinbo Zhang
- 刊名：Journal of the American Chemical Society
- 出版年：2016
- 出版时间：August 17, 2016
- 年：2016
- 卷：138
- 期：32
- 页码：10226-10231
- 全文大小：378K
- 年卷期：0
- ISSN：1520-5126
文摘
Flexible power sources with high energy density are crucial for the realization of next-generation flexible electronics. Theoretically, rechargeable flexible zinc–air (Zn–air) batteries could provide high specific energy, while their large-scale applications are still greatly hindered by high cost and resources scarcity of noble-metal-based oxygen evolution reaction (OER)/oxygen reduction reaction (ORR) electrocatalysts as well as inferior mechanical properties of the air cathode. Combining metallic Co<sub>4sub>N with superior OER activity and Co–N–C with perfect ORR activity on a free-standing and flexible electrode could be a good step for flexible Zn–air batteries, while lots of difficulties need to be overcome. Herein, as a proof-of-concept experiment, we first propose a strategy for in situ coupling of strung Co<sub>4sub>N and intertwined N–C fibers, by pyrolyzation of the novel pearl-like ZIF-67/polypyrrole nanofibers network rooted on carbon cloth. Originating from the synergistic effect of Co<sub>4sub>N and Co–N–C and the stable 3D interconnected conductive network structure, the obtained free-standing and highly flexible bifunctional oxygen electrode exhibits excellent electrocatalytic activity and stability for both OER and ORR in terms of low overpotential (310 mV at 10 mA cm<sup>–2sup>) for OER, a positive half-wave potential (0.8 V) for ORR, and a stable current density retention for at least 20 h, and especially, the obtained Zn–air batteries exhibit a low discharge–charge voltage gap (1.09 V at 50 mA cm<sup>–2sup>) and long cycle life (up to 408 cycles). Furthermore, the perfect bendable and twistable and rechargeable properties of the flexible Zn–air battery particularly make it a potentially power portable and wearable electronic device.